s also called as the application level gateway or the proxy server. It is a form of computer and networking technology designed exclusively for the Internet and network needs of different individuals and business institutions. In particular, a proxy acts as the mediator between different computers within the company’s Internet, local network, or within any other large-scale network. A proxy starts its task when a specific computer within the local network requests for a piece of incoming data. In such case, the proxy makes sure that the piece of incoming data successfully enters and passes through any of its ports. The pieces of data are then forwarded and sent to the unit requesting it. This is done through a different port. Therefore, by providing a way of forbidding the direct access between the networks, a proxy may prevent unauthorized individuals, particularly hackers from acquiring sensitive and important information, such as the group’s internal addresses. There are two types of proxy: the SMTP or Simple Mail Transfer Protocol proxy and the HTTP or Hypertext Transfer Protocol proxy. The SMTP proxy serves as the gateway for emails while the HTTP proxy serves as the Internet access gateway. Aside from controlling the external networks’ access level, a proxy may also set access restriction to online resources for computers in the local network. This is especially useful when the network administrator should prevent users from accessing restricted websites. A proxy is also capable of caching Web pages. This enables the main computer to keep copies of Web pages downloaded in its hard disk. When an external URL is requested by a computer within the local network, a copy of that external URL is also kept in the server. Moreover, when the same URL is requested by another computer at a later time, the proxy may provide the stored copy rather the acquiring the original URL from the Internet. This is done to minimize the time for obtaining information.